Chemokine receptor expression in CD4 T lymphocytes from XLP patients. (A) Mean ± SEM of the percentage of CXCR3⁺ or CCR4⁺ T lymphocytes within the CD4⁺ subpopulation (memory T_H1 or memory T_H2 lymphocytes, respectively) in 3 PBMC samples from XLP patients 9 and 4 obtained between November 2002 and April 2003. Shaded area in the graph corresponds to mean ± SEM of healthy control subjects performed simultaneously (n = 7). (B) An example of cytometric analysis (lymphocyte gate) of a healthy control and patient no. 9.